// Builder.cs - customizations to Gtk.Builder
//
// Authors: Stephane Delcroix  <stephane@delcroix.org>
// The biggest part of this code is adapted from glade#, by
//	Ricardo Fernández Pascual <ric@users.sourceforge.net>
//	Rachel Hestilow <hestilow@ximian.com>
//
// Copyright (c) 2002 Ricardo Fernández Pascual
// Copyright (c) 2003 Rachel Hestilow
// Copyright (c) 2008 Novell, Inc.
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of version 2 of the Lesser GNU General
// Public License as published by the Free Software Foundation.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this program; if not, write to the
// Free Software Foundation, Inc., 59 Temple Place - Suite 330,
// Boston, MA 02111-1307, USA.

namespace Gtk {

	using System;
	using System.IO;
	using System.Reflection;
	using System.Runtime.InteropServices;
	using System.Text;

	public partial class Builder {

		[System.Serializable]
		public class HandlerNotFoundException : SystemException {
			string handler_name;
			string signal_name;
			System.Reflection.EventInfo evnt;
			Type delegate_type;

			public HandlerNotFoundException(string handler_name, string signal_name,
							 System.Reflection.EventInfo evnt, Type delegate_type)
				: this(handler_name, signal_name, evnt, delegate_type, null) {
			}

			public HandlerNotFoundException(string handler_name, string signal_name,
							 System.Reflection.EventInfo evnt, Type delegate_type, Exception inner)
				: base("No handler " + handler_name + " found for signal " + signal_name,
					inner) {
				this.handler_name = handler_name;
				this.signal_name = signal_name;
				this.evnt = evnt;
				this.delegate_type = delegate_type;
			}

			public HandlerNotFoundException(string message, string handler_name, string signal_name,
							 System.Reflection.EventInfo evnt, Type delegate_type)
				: base((message != null) ? message : "No handler " + handler_name + " found for signal " + signal_name,
					null) {
				this.handler_name = handler_name;
				this.signal_name = signal_name;
				this.evnt = evnt;
				this.delegate_type = delegate_type;
			}

			protected HandlerNotFoundException(System.Runtime.Serialization.SerializationInfo info, System.Runtime.Serialization.StreamingContext context)
				: base(info, context) {
				handler_name = info.GetString("HandlerName");
				signal_name = info.GetString("SignalName");
				evnt = info.GetValue("Event", typeof(System.Reflection.EventInfo)) as System.Reflection.EventInfo;
				delegate_type = info.GetValue("DelegateType", typeof(Type)) as Type;
			}

			public string HandlerName {
				get {
					return handler_name;
				}
			}

			public string SignalName {
				get {
					return signal_name;
				}
			}

			public System.Reflection.EventInfo Event {
				get {
					return evnt;
				}
			}

			public Type DelegateType {
				get {
					return delegate_type;
				}
			}

			public override void GetObjectData(System.Runtime.Serialization.SerializationInfo info, System.Runtime.Serialization.StreamingContext context) {
				base.GetObjectData(info, context);
				info.AddValue("HandlerName", handler_name);
				info.AddValue("SignalName", signal_name);
				info.AddValue("Event", evnt);
				info.AddValue("DelegateType", delegate_type);
			}
		}


		[AttributeUsage(AttributeTargets.Field)]
		public class ObjectAttribute : Attribute {
			private string name;
			private bool specified;

			public ObjectAttribute(string name) {
				specified = true;
				this.name = name;
			}

			public ObjectAttribute() {
				specified = false;
			}

			public string Name {
				get { return name; }
			}

			public bool Specified {
				get { return specified; }
			}
		}

		public IntPtr GetRawObject(string name) {
			IntPtr native_name = GLib.Marshaller.StringToPtrGStrdup(name);
			IntPtr raw_ret = gtk_builder_get_object(Handle, native_name);
			GLib.Marshaller.Free(native_name);
			return raw_ret;
		}

		public Builder(System.IO.Stream s) : this(s, null) {
		}

		public Builder(System.IO.Stream s, string translation_domain) {
			if (s == null)
				throw new ArgumentNullException("s");

			AddFromStream(s);
			TranslationDomain = translation_domain;
		}

		public Builder(string resource_name) : this(Assembly.GetCallingAssembly(), resource_name, null) {
		}

		public Builder(string resource_name, string translation_domain)
			: this(Assembly.GetCallingAssembly(), resource_name, translation_domain) {
		}

		public Builder(Assembly assembly, string resource_name, string translation_domain) : this() {
			if (GetType() != typeof(Builder))
				throw new InvalidOperationException("Cannot chain to this constructor from subclasses.");

			if (assembly == null)
				assembly = Assembly.GetCallingAssembly();

			System.IO.Stream s = assembly.GetManifestResourceStream(resource_name);
			if (s == null)
				throw new ArgumentException("Cannot get resource file '" + resource_name + "'",
											 "resource_name");

			AddFromStream(s);
			TranslationDomain = translation_domain;
		}

		public void Autoconnect(object handler) {
			BindFields(handler);
			(new SignalConnector(this, handler)).ConnectSignals();
		}

		public void Autoconnect(Type handler_class) {
			BindFields(handler_class);
			(new SignalConnector(this, handler_class)).ConnectSignals();
		}

		class SignalConnector {
			Builder builder;
			Type handler_type;
			object handler;

			public SignalConnector(Builder builder, object handler) {
				this.builder = builder;
				this.handler = handler;
				handler_type = handler.GetType();
			}

			public SignalConnector(Builder builder, Type handler_type) {
				this.builder = builder;
				this.handler = null;
				this.handler_type = handler_type;
			}

			[DllImport(Global.GtkNativeDll, CallingConvention = CallingConvention.Cdecl)]
			static extern void gtk_builder_connect_signals_full(IntPtr raw, GtkSharp.BuilderConnectFuncNative func, IntPtr user_data);

			public void ConnectSignals() {
				GtkSharp.BuilderConnectFuncWrapper func_wrapper = new GtkSharp.BuilderConnectFuncWrapper(new BuilderConnectFunc(ConnectFunc));
				gtk_builder_connect_signals_full(builder.Handle, func_wrapper.NativeDelegate, IntPtr.Zero);
			}

			public void ConnectFunc(Builder builder, GLib.Object objekt, string signal_name, string handler_name, GLib.Object connect_object, GLib.ConnectFlags flags) {
				/* search for the event to connect */
				System.Reflection.MemberInfo[] evnts = objekt.GetType().
					FindMembers(System.Reflection.MemberTypes.Event,
						 System.Reflection.BindingFlags.Instance
						 | System.Reflection.BindingFlags.Static
						 | System.Reflection.BindingFlags.Public
						 | System.Reflection.BindingFlags.NonPublic,
						 new System.Reflection.MemberFilter(SignalFilter), signal_name);
				foreach (System.Reflection.EventInfo ei in evnts) {
					bool connected = false;
					System.Reflection.MethodInfo add = ei.GetAddMethod();
					System.Reflection.ParameterInfo[] addpi = add.GetParameters();
					if (addpi.Length == 1) { /* this should be always true, unless there's something broken */
						Type delegate_type = addpi[0].ParameterType;

						/* look for an instance method */
						if (connect_object != null || handler != null)
							try {
								Delegate d = Delegate.CreateDelegate(delegate_type, connect_object != null ? connect_object : handler, handler_name);
								add.Invoke(objekt, new object[] { d });
								connected = true;

								/* Unmerged change from project 'gtk(net5.0)'
                                Before:
                                                            throw e;
                                                        }
                                After:
                                                            throw;
                                                        }
                                */
							} catch (ArgumentException) { /* ignore if there is not such instance method */
							}

						/* look for a static method if no instance method has been found */
						if (!connected && handler_type != null)
							try {
								Delegate d = Delegate.CreateDelegate(delegate_type, handler_type, handler_name);
								add.Invoke(objekt, new object[] { d });
								connected = true;
							} catch (ArgumentException) { /* ignore if there is not such static method */
							}

						if (!connected) {
							string msg = ExplainError(ei.Name, delegate_type, handler_type, handler_name);
							throw new HandlerNotFoundException(msg, handler_name, signal_name, ei, delegate_type);
						}
					}
				}
			}

			static bool SignalFilter(System.Reflection.MemberInfo m, object filterCriteria) {
				string signame = (filterCriteria as string);
				object[] attrs = m.GetCustomAttributes(typeof(GLib.SignalAttribute), false);
				if (attrs.Length > 0) {
					foreach (GLib.SignalAttribute a in attrs) {
						if (signame == a.CName) {
							return true;
						}
					}
					return false;
				} else {
					/* this tries to match the names when no attibutes are present.
					   It is only a fallback. */
					signame = signame.ToLower().Replace("_", "");
					string evname = m.Name.ToLower();
					return signame == evname;
				}
			}

			static string GetSignature(System.Reflection.MethodInfo method) {
				if (method == null)
					return null;

				System.Reflection.ParameterInfo[] parameters = method.GetParameters();
				System.Text.StringBuilder sb = new System.Text.StringBuilder();
				sb.Append('(');
				foreach (System.Reflection.ParameterInfo info in parameters) {
					sb.Append(info.ParameterType.ToString());
					sb.Append(',');
				}
				if (sb.Length != 0)
					sb.Length--;

				sb.Append(')');
				return sb.ToString();
			}

			static string GetSignature(Type delegate_type) {
				System.Reflection.MethodInfo method = delegate_type.GetMethod("Invoke");
				return GetSignature(method);
			}

			const System.Reflection.BindingFlags flags = System.Reflection.BindingFlags.NonPublic |
							System.Reflection.BindingFlags.Public |
							System.Reflection.BindingFlags.Static |
							System.Reflection.BindingFlags.Instance;
			static string GetSignature(Type klass, string method_name) {
				try {
					System.Reflection.MethodInfo method = klass.GetMethod(method_name, flags);
					return GetSignature(method);
				} catch {
					// May be more than one method with that name and none matches
					return null;
				}
			}


			static string ExplainError(string event_name, Type deleg, Type klass, string method) {
				if (deleg == null || klass == null || method == null)
					return null;

				System.Text.StringBuilder sb = new System.Text.StringBuilder();
				string expected = GetSignature(deleg);
				string actual = GetSignature(klass, method);
				if (actual == null)
					return null;
				sb.AppendFormat("The handler for the event {0} should take '{1}', " +
					"but the signature of the provided handler ('{2}') is '{3}'\n",
					event_name, expected, method, actual);
				return sb.ToString();
			}

		}

		void AddFromStream(Stream stream) {
			var size = (int)stream.Length;
			var buffer = new byte[size];
			stream.Read(buffer, 0, size);
			stream.Close();

			// If buffer contains a BOM, omit it while reading, otherwise AddFromString(text) crashes
			var offset = 0;
			if (size >= 3 && buffer[0] == 0xEF && buffer[1] == 0xBB && buffer[2] == 0xBF) {
				offset = 3;
			}

			var text = Encoding.UTF8.GetString(buffer, offset, size - offset);
			AddFromString(text);
		}

		void BindFields(object target) {
			BindFields(target, target.GetType());
		}

		void BindFields(Type type) {
			BindFields(null, type);
		}

		void BindFields(object target, Type type) {
			System.Reflection.BindingFlags flags = System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.DeclaredOnly;
			if (target != null)
				flags |= System.Reflection.BindingFlags.Instance;
			else
				flags |= System.Reflection.BindingFlags.Static;

			do {
				System.Reflection.FieldInfo[] fields = type.GetFields(flags);
				if (fields == null)
					return;

				foreach (System.Reflection.FieldInfo field in fields) {
					object[] attrs = field.GetCustomAttributes(typeof(ObjectAttribute), false);
					if (attrs == null || attrs.Length == 0)
						continue;
					// The widget to field binding must be 1:1, so only check
					// the first attribute.
					ObjectAttribute attr = (ObjectAttribute)attrs[0];
					GLib.Object gobject;
					if (attr.Specified)
						gobject = GetObject(attr.Name);
					else
						gobject = GetObject(field.Name);

					if (gobject != null)
						try {
							field.SetValue(target, gobject, flags, null, null);
						} catch (Exception e) {
							Console.WriteLine("Unable to set value for field " + field.Name);
							throw;
						}
				}
				type = type.BaseType;
			}
			while (type != typeof(object) && type != null);
		}
	}
}